The smell of sewage permeates almost every cell. This is one of the more pungent observations in a report about conditions in Limerick Prison, published last week by the inspector of prisons, Judge Michael Reilly.
Unpleasant though it is, the thought is unlikely to keep many of us awake at night: after all, what are prisons for, if not the containment of human filth?
Judge Reilly's depiction of Limerick Prison is undoubtedly damning but hardly all that shocking. There is a dreary familiarity to his depiction of the institution as an unsanitary, overcrowded and decrepit hellhole, wherein intimidation by some prison officers is rife.
Like an inveterate old lag returning to his usual cell, we have been around this block before.
Nevertheless, there are eye-catching details in Reilly's report that offer an evocative portrait of life on the inside.
Apparently, the windows in all the cells in Limerick Prison are broken, letting in the rain. Despite what should be an abundance of fresh air-conditioning, however, the atmosphere in the cells is stifling and fetid, as prisoners use all manner of garbage to block the cracks and gaps during winter.
Many of the cells have no toilets and many prisoners are forced to share slop-out pots. The prison's plumbing is banjaxed.
In the prevailing economic climate, it's refreshing to discover that money alone is not the cause of the mess in which the prison is enmired. While several wings date back to 1821, the remainder of the facility is of comparatively recent vintage, encompassing a new school, medical centre, gym, recreation hall and 150 reasonably well-equipped cells.
However, even these more modern areas have fallen into disrepair, as much through negligence as lack of resources.
Judge Reilly acknowledges that the conditions are exacerbated by the issue of gangs and the constant threat of violence breaking out between rival factions.
Many prisoners are effectively locked down for 23 hours a day, some for their own protection, some for the protection of others.
These tensions are further heightened by the attitudes of a minority of prison staff, who take evident pleasure in goading and mistreating inmates.
Judge Reilly take pains to stress that Limerick Prison is not unique and he's absolutely right. We know what is happening in our prisons and we clearly don't care.
There are good reasons for this. Sickened by criminal depravity, especially among those involved in the high-stakes drugs trade, we rejoice when the bad guys are locked up and regard hard time as their just deserts.
However, for reasons of self-interest, if nothing else, we would be wise to reappraise the popular view that anyone who ends up in prison for whatever reason deserves not just loss of freedom but a brutalising trip to hell.
Public indifference to prison conditions stems largely from the convenient belief that everyone who bears the label 'criminal' is irredeemable, subhuman, psycho scum and so whatever happens to them behind bars is justified.
In reality, the incarcerated population includes hundreds of non-violent individuals who have been traumatised for life in our prisons because they made a bad judgment or even a series of bad judgments, usually when they were young, stupid and high.
Sooner or later, almost every prisoner receives a release date. Having repaid their debt to society, they re-emerge with all the problems they had when they went inside and a whole slew of new problems fomented by their treatment while in prison.
It is the height of ignorance to assume that imprisonment in degrading conditions will transform a troubled delinquent into a model citizen who will never reoffend. Ultimately, therefore, the best arguments for the more humane treatment of prisoners are about us rather than them.
Yes, there are monsters and beasts in our prisons, people whose humanity has been ripped to bloody shreds. Most didn't go in that way, but thanks to the twisted logic of a dysfunctional penal system, you can be sure that is how they'll come out.